/* eslint-disable prefer-object-spread */
/* eslint-disable no-underscore-dangle */
/* eslint-disable prefer-promise-reject-errors */
import XLSX from "xlsx";

/**
 * 导入excel的函数
 * @param {*} file 
 */
const importsExcel = (file: any) => {
    return new Promise((resolve, reject) => {
        // 获取上传的文件对象
        const { files } = file.target;
        // 通过FileReader对象读取文件
        const fileReader = new FileReader();

        fileReader.onload = event => {
            // 异步操作  excel文件加载完成以后触发
            try {
                // @ts-ignore
                const { result } = event.target;
                // 以二进制流方式读取得到整份excel表格对象
                const workbook = XLSX.read(result, { type: 'binary' });
                let data: any = []; // 存储获取到的数据
                // 遍历每张工作表进行读取（这里默认只读取第一张表）
                Object.keys(workbook.Sheets).forEach(sheet => {
                    if (workbook.Sheets.hasOwnProperty(sheet)) {
                        data = data.concat(XLSX.utils.sheet_to_json(workbook.Sheets[sheet]));
                    }
                })
                resolve(data);
                // 导出数据
            } catch (e) {
                // 这里可以抛出文件类型错误不正确的相关提示
                reject("失败");
                // 导出失败
            }
        };
        // 以二进制方式打开文件
        fileReader.readAsBinaryString(files[0]);
    })

}
/**
 * 导出excel
 * @param {*} headers 
 * @param {*} data 
 * @param {*} fileName 
 */

const exportExcel = (headers: any[], data: any[], fileName = 'demo.xlsx') => {

    const _headers = headers
        .map((item: { key: any; title: any; }, i: number) => Object.assign({}, { key: item.key, title: item.title, position: String.fromCharCode(65 + i) + 1 }))
        .reduce((prev: any, next: { position: any; key: any; title: any; }) => Object.assign({}, prev, { [next.position]: { key: next.key, v: next.title } }), {});

    const _data = data
        .map((item: { [x: string]: any; }, i: number) => headers.map((key: { key: string | number; }, j: number) => Object.assign({}, { content: item[key.key], position: String.fromCharCode(65 + j) + (i + 2) })))
        // 对刚才的结果进行降维处理（二维数组变成一维数组）
        .reduce((prev: any, next: any) => prev.concat(next))
        // 转换成 worksheet 需要的结构
        .reduce((prev: any, next: { position: any; content: any; }) => Object.assign({}, prev, { [next.position]: { v: next.content } }), {});

    // 合并 headers 和 data
    const output = Object.assign({}, _headers, _data);
    // 获取所有单元格的位置
    const outputPos = Object.keys(output);
    // 计算出范围 ,["A1",..., "H2"]
    const ref = `${outputPos[0]}:${outputPos[outputPos.length - 1]}`;

    // 构建 workbook 对象
    const wb = {
        SheetNames: ['mySheet'],
        Sheets: {
            mySheet: Object.assign(
                {},
                output,
                {
                    '!ref': ref,
                    '!cols': [{ wpx: 45 }, { wpx: 100 }, { wpx: 200 }, { wpx: 80 }, { wpx: 150 }, { wpx: 100 }, { wpx: 300 }, { wpx: 300 }],
                },
            ),
        },
    };

    // 导出 Excel
    XLSX.writeFile(wb, fileName);

}


export {
    importsExcel,
    exportExcel
}